Not sure whats going on

Not sure what is going on. The flashing lights are weird. And my screen goes from bright to darker when lights are flashing.
also when loading the map I get a white loading screen with a red text that says MISSING!

Quote from Jan

Correct installation of the modification (MISSING TEXTURE problem)

I did this step when installing so that did not work for me.
I am gonna try the first thing you wrote.

Quote from Jan

This one seemed to work. Now I just want to get rid of all the annoying random crashes